Toyota Tundra Service Manual: Terminals Of Ecu

TERMINALS OF ECU

1. CHECK AIR CONDITIONING AMPLIFIER

(a) Disconnect the J19 air conditioning amplifier connector.

(b) Measure the resistance and voltage according to the value(s) in the table below.

Terminal No. (Symbol)	Wiring Color	Terminal Description	Condition	Specified Condition
J19-1 (IG+) - J19-14 (GND)	B - W-B	Ignition power supply	Ignition switch ON	11 to 14 V
J19-1 (IG+) - J19-14 (GND)	B - W-B	Ignition power supply	Ignition switch OFF	Below 1 V
J19-21 (B) - J19-14 (GND)	GR - W-B	Battery power source	Always	11 to 14 V
J19-14 (GND) - Body ground	W-B - Body ground	Ground	Always	Below 1 Ω
J19-37 (LIN1) - J19-14 (GND)	SB - W-B	LIN communication signal	Ignition switch ON	Pulse generation

(d) Measure the voltage according to the value(s) in the table below.

Terminal No. (Symbol)	Wiring Color	Terminal Description	Condition	Specified Condition
J19-38 (RDEF) - J19-14 (GND)	Y - W-B	Defogger relay	Ignition switch ON, rear window defogger switch off	11 to 14 V
J19-38 (RDEF) - J19-14 (GND)	Y - W-B	Defogger relay	Ignition switch ON, rear window defogger switch on	Below 1 V

2. CHECK AIR CONDITIONING CONTROL ASSEMBLY

(a) Disconnect the J127 air conditioning control assembly connector.

(b) Measure the voltage and resistance according to the value(s) in the table below.

Terminal No. (Symbol)	Wiring Color	Terminal Description	Condition	Specified Condition
J127-4 (IG+) - J127-5 (GND)	Y - W-B	Ignition power supply	Ignition switch ON	11 to 14 V
J127-4 (IG+) - J127-5 (GND)	Y - W-B	Ignition power supply	Ignition switch OFF	Below 1 V
J127-5 (GND) - Body ground	W-B - Body ground	Ground	Always	Below 1 Ω
J127-7 (STX) - J127-5 (GND)	SB - W-B	LIN communication signal	Ignition switch ON	Pulse generation

Toyota Tundra Service Manual > Air Conditioning System(for Automatic Air Conditioning System): Blower Motor Circuit
DESCRIPTION The blower motor is operated by signals from the air conditioning amplifier. Blower motor speed signals are transmitted by changes in the duty ratio. Duty Ratio: The duty ratio is the ratio of the blower motor OFF time (B) to the total of the blower motor ON and OFF time (A + B). The blo ...

Toyota Tundra Owners Manual